json_config.hpp - openbmc/phosphor-fan-presence - Gitiles

 /**
  * Copyright © 2020 IBM Corporation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 #pragma once

 #include "sdbusplus.hpp"

 #include <nlohmann/json.hpp>
 #include <phosphor-logging/log.hpp>
 #include <sdbusplus/bus.hpp>
 #include <sdeventplus/source/signal.hpp>

 #include <filesystem>
 #include <format>
 #include <fstream>

 namespace phosphor::fan
 {

 namespace fs = std::filesystem;
 using json = nlohmann::json;
 using namespace phosphor::logging;

 constexpr auto confOverridePath = "/etc/phosphor-fan-presence";
 constexpr auto confBasePath = "/usr/share/phosphor-fan-presence";
 constexpr auto confCompatServ = "xyz.openbmc_project.EntityManager";
 constexpr auto confCompatIntf =
     "xyz.openbmc_project.Inventory.Decorator.Compatible";
 constexpr auto confCompatProp = "Names";

 /**
  * @class NoConfigFound - A no JSON configuration found exception
  *
  * A no JSON configuration found exception that is used to denote that a JSON
  * configuration has not been found yet.
  */
 class NoConfigFound : public std::runtime_error
 {
   public:
     NoConfigFound() = delete;
     NoConfigFound(const NoConfigFound&) = delete;
     NoConfigFound(NoConfigFound&&) = delete;
     NoConfigFound& operator=(const NoConfigFound&) = delete;
     NoConfigFound& operator=(NoConfigFound&&) = delete;
     ~NoConfigFound() = default;

     /**
      * @brief No JSON configuration found exception object
      *
      * When attempting to find the JSON configuration file(s), a NoConfigFound
      * exception can be thrown to denote that at that time finding/loading the
      * JSON configuration file(s) for a fan application failed. Details on what
      * application and JSON configuration file that failed to be found will be
      * logged resulting in the application being terminated.
      *
      * @param[in] details - Additional details
      */
     NoConfigFound(const std::string& appName, const std::string& fileName) :
         std::runtime_error(std::format("JSON configuration not found [Could "
                                        "not find fan {} conf file {}]",
                                        appName, fileName)
                                .c_str())
     {}
 };

 class JsonConfig
 {
   public:
     /**
      * @brief Get the object paths with the compatible interface
      *
      * Retrieve all the object paths implementing the compatible interface for
      * configuration file loading.
      */
     std::vector<std::string>& getCompatObjPaths()
     {
         using SubTreeMap =
             std::map<std::string,
                      std::map<std::string, std::vector<std::string>>>;
         SubTreeMap subTreeObjs = util::SDBusPlus::getSubTreeRaw(
             util::SDBusPlus::getBus(), "/", confCompatIntf, 0);

         static std::vector<std::string> paths;
         for (auto& [path, serviceMap] : subTreeObjs)
         {
             // Only save objects under confCompatServ
             if (serviceMap.find(confCompatServ) != serviceMap.end())
             {
                 paths.emplace_back(path);
             }
         }
         return paths;
     }

     /**
      * @brief Constructor
      *
      * Attempts to set the list of compatible values from the compatible
      * interface and call the fan app's function to load its config file(s). If
      * the compatible interface is not found, it subscribes to the
      * interfacesAdded signal for that interface on the compatible service
      * defined above.
      *
      * @param[in] func - Fan app function to call to load its config file(s)
      */
     JsonConfig(std::function<void()> func) : _loadFunc(func)
     {
         std::vector<std::string> compatObjPaths;

         _match = std::make_unique<sdbusplus::bus::match_t>(
             util::SDBusPlus::getBus(),
             sdbusplus::bus::match::rules::interfacesAdded() +
                 sdbusplus::bus::match::rules::sender(confCompatServ),
             std::bind(&JsonConfig::compatIntfAdded, this,
                       std::placeholders::_1));

         try
         {
             compatObjPaths = getCompatObjPaths();
         }
         catch (const util::DBusMethodError&)
         {
             // Compatible interface does not exist on any dbus object yet
         }

         if (!compatObjPaths.empty())
         {
             for (auto& path : compatObjPaths)
             {
                 try
                 {
                     // Retrieve json config compatible relative path
                     // locations (last one found will be what's used if more
                     // than one dbus object implementing the compatible
                     // interface exists).
                     _confCompatValues =
                         util::SDBusPlus::getProperty<std::vector<std::string>>(
                             util::SDBusPlus::getBus(), path, confCompatIntf,
                             confCompatProp);
                 }
                 catch (const util::DBusError&)
                 {
                     // Compatible property unavailable on this dbus object
                     // path's compatible interface, ignore
                 }
             }
             try
             {
                 _loadFunc();
             }
             catch (const NoConfigFound&)
             {
                 // The Decorator.Compatible interface is not unique to one
                 // single object on DBus so this should not be treated as a
                 // failure, wait for interfacesAdded signal.
             }
         }
         else
         {
             // Check if required config(s) are found not needing the
             // compatible interface, otherwise this is intended to catch the
             // exception thrown by the getConfFile function when the
             // required config file was not found. This would then result in
             // waiting for the compatible interfacesAdded signal
             try
             {
                 _loadFunc();
             }
             catch (const NoConfigFound&)
             {
                 // Wait for compatible interfacesAdded signal
             }
         }
     }

     /**
      * @brief InterfacesAdded callback function for the compatible interface.
      *
      * @param[in] msg - The D-Bus message contents
      *
      * If the compatible interface is found, it uses the compatible property on
      * the interface to set the list of compatible values to be used when
      * attempting to get a configuration file. Once the list of compatible
      * values has been updated, it calls the load function.
      */
     void compatIntfAdded(sdbusplus::message_t& msg)
     {
         if (!_compatibleName.empty())
         {
             // Do not process the interfaceAdded signal if one compatible name
             // has been successfully used to get config files
             return;
         }
         sdbusplus::message::object_path op;
         std::map<std::string,
                  std::map<std::string, std::variant<std::vector<std::string>>>>
             intfProps;

         msg.read(op, intfProps);

         if (intfProps.find(confCompatIntf) == intfProps.end())
         {
             return;
         }

         const auto& props = intfProps.at(confCompatIntf);
         // Only one dbus object with the compatible interface is used at a time
         _confCompatValues =
             std::get<std::vector<std::string>>(props.at(confCompatProp));
         _loadFunc();
     }

     /**
      * Get the json configuration file. The first location found to contain
      * the json config file for the given fan application is used from the
      * following locations in order.
      * 1.) From the confOverridePath location
      * 2.) From the default confBasePath location
      * 3.) From config file found using an entry from a list obtained from an
      * interface's property as a relative path extension on the base path where:
      *     interface = Interface set in confCompatIntf with the property
      *     property = Property set in confCompatProp containing a list of
      *                subdirectories in priority order to find a config
      *
      * @brief Get the configuration file to be used
      *
      * @param[in] appName - The phosphor-fan-presence application name
      * @param[in] fileName - Application's configuration file's name
      * @param[in] isOptional - Config file is optional, default to 'false'
      *
      * @return filesystem path
      *     The filesystem path to the configuration file to use
      */
     static const fs::path getConfFile(const std::string& appName,
                                       const std::string& fileName,
                                       bool isOptional = false)
     {
         // Check override location
         fs::path confFile = fs::path{confOverridePath} / appName / fileName;
         if (fs::exists(confFile))
         {
             return confFile;
         }

         // If the default file is there, use it
         confFile = fs::path{confBasePath} / appName / fileName;
         if (fs::exists(confFile))
         {
             return confFile;
         }

         // Look for a config file at each entry relative to the base
         // path and use the first one found
         auto it =
             std::find_if(_confCompatValues.begin(), _confCompatValues.end(),
                          [&confFile, &appName, &fileName](const auto& value) {
             confFile = fs::path{confBasePath} / appName / value / fileName;
             _compatibleName = value;
             return fs::exists(confFile);
         });
         if (it == _confCompatValues.end())
         {
             confFile.clear();
             _compatibleName.clear();
         }

         if (confFile.empty() && !isOptional)
         {
             throw NoConfigFound(appName, fileName);
         }

         return confFile;
     }

     /**
      * @brief Load the JSON config file
      *
      * @param[in] confFile - File system path of the configuration file to load
      *
      * @return Parsed JSON object
      *     The parsed JSON configuration file object
      */
     static const json load(const fs::path& confFile)
     {
         std::ifstream file;
         json jsonConf;

         if (!confFile.empty() && fs::exists(confFile))
         {
             log<level::INFO>(
                 std::format("Loading configuration from {}", confFile.string())
                     .c_str());
             file.open(confFile);
             try
             {
                 // Enable ignoring `//` or `/* */` comments
                 jsonConf = json::parse(file, nullptr, true, true);
             }
             catch (const std::exception& e)
             {
                 log<level::ERR>(
                     std::format(
                         "Failed to parse JSON config file: {}, error: {}",
                         confFile.string(), e.what())
                         .c_str());
                 throw std::runtime_error(
                     std::format(
                         "Failed to parse JSON config file: {}, error: {}",
                         confFile.string(), e.what())
                         .c_str());
             }
         }
         else
         {
             log<level::ERR>(std::format("Unable to open JSON config file: {}",
                                         confFile.string())
                                 .c_str());
             throw std::runtime_error(
                 std::format("Unable to open JSON config file: {}",
                             confFile.string())
                     .c_str());
         }

         return jsonConf;
     }

     /**
      * @brief Return the compatible values property
      *
      * @return const std::vector<std::string>& - The values
      */
     static const std::vector<std::string>& getCompatValues()
     {
         return _confCompatValues;
     }

   private:
     /* Load function to call for a fan app to load its config file(s). */
     std::function<void()> _loadFunc;

     /**
      * @brief The interfacesAdded match that is used to wait
      *        for the Inventory.Decorator.Compatible interface to show up.
      */
     std::unique_ptr<sdbusplus::bus::match_t> _match;

     /**
      * @brief List of compatible values from the compatible interface
      *
      * Only supports a single instance of the compatible interface on a dbus
      * object. If more than one dbus object exists with the compatible
      * interface, the last one found will be the list of compatible values used.
      */
     inline static std::vector<std::string> _confCompatValues;

     /**
      * @brief The compatible value that is currently used to load configuration
      *
      * The value extracted from the achieved property value list that is used
      * as a sub-folder to append to the configuration location and really
      * contains the configruation files
      */

     inline static std::string _compatibleName;
 };

 } // namespace phosphor::fan
	/**
	* Copyright © 2020 IBM Corporation
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	#pragma once

	#include "sdbusplus.hpp"

	#include <nlohmann/json.hpp>
	#include <phosphor-logging/log.hpp>
	#include <sdbusplus/bus.hpp>
	#include <sdeventplus/source/signal.hpp>

	#include <filesystem>
	#include <format>
	#include <fstream>

	namespace phosphor::fan
	{

	namespace fs = std::filesystem;
	using json = nlohmann::json;
	using namespace phosphor::logging;

	constexpr auto confOverridePath = "/etc/phosphor-fan-presence";
	constexpr auto confBasePath = "/usr/share/phosphor-fan-presence";
	constexpr auto confCompatServ = "xyz.openbmc_project.EntityManager";
	constexpr auto confCompatIntf =
	"xyz.openbmc_project.Inventory.Decorator.Compatible";
	constexpr auto confCompatProp = "Names";

	/**
	* @class NoConfigFound - A no JSON configuration found exception
	*
	* A no JSON configuration found exception that is used to denote that a JSON
	* configuration has not been found yet.
	*/
	class NoConfigFound : public std::runtime_error
	{
	public:
	NoConfigFound() = delete;
	NoConfigFound(const NoConfigFound&) = delete;
	NoConfigFound(NoConfigFound&&) = delete;
	NoConfigFound& operator=(const NoConfigFound&) = delete;
	NoConfigFound& operator=(NoConfigFound&&) = delete;
	~NoConfigFound() = default;

	/**
	* @brief No JSON configuration found exception object
	*
	* When attempting to find the JSON configuration file(s), a NoConfigFound
	* exception can be thrown to denote that at that time finding/loading the
	* JSON configuration file(s) for a fan application failed. Details on what
	* application and JSON configuration file that failed to be found will be
	* logged resulting in the application being terminated.
	*
	* @param[in] details - Additional details
	*/
	NoConfigFound(const std::string& appName, const std::string& fileName) :
	std::runtime_error(std::format("JSON configuration not found [Could "
	"not find fan {} conf file {}]",
	appName, fileName)
	.c_str())
	{}
	};

	class JsonConfig
	{
	public:
	/**
	* @brief Get the object paths with the compatible interface
	*
	* Retrieve all the object paths implementing the compatible interface for
	* configuration file loading.
	*/
	std::vector<std::string>& getCompatObjPaths()
	{
	using SubTreeMap =
	std::map<std::string,
	std::map<std::string, std::vector<std::string>>>;
	SubTreeMap subTreeObjs = util::SDBusPlus::getSubTreeRaw(
	util::SDBusPlus::getBus(), "/", confCompatIntf, 0);

	static std::vector<std::string> paths;
	for (auto& [path, serviceMap] : subTreeObjs)
	{
	// Only save objects under confCompatServ
	if (serviceMap.find(confCompatServ) != serviceMap.end())
	{
	paths.emplace_back(path);
	}
	}
	return paths;
	}

	/**
	* @brief Constructor
	*
	* Attempts to set the list of compatible values from the compatible
	* interface and call the fan app's function to load its config file(s). If
	* the compatible interface is not found, it subscribes to the
	* interfacesAdded signal for that interface on the compatible service
	* defined above.
	*
	* @param[in] func - Fan app function to call to load its config file(s)
	*/
	JsonConfig(std::function<void()> func) : _loadFunc(func)
	{
	std::vector<std::string> compatObjPaths;

	_match = std::make_unique<sdbusplus::bus::match_t>(
	util::SDBusPlus::getBus(),
	sdbusplus::bus::match::rules::interfacesAdded() +
	sdbusplus::bus::match::rules::sender(confCompatServ),
	std::bind(&JsonConfig::compatIntfAdded, this,
	std::placeholders::_1));

	try
	{
	compatObjPaths = getCompatObjPaths();
	}
	catch (const util::DBusMethodError&)
	{
	// Compatible interface does not exist on any dbus object yet
	}

	if (!compatObjPaths.empty())
	{
	for (auto& path : compatObjPaths)
	{
	try
	{
	// Retrieve json config compatible relative path
	// locations (last one found will be what's used if more
	// than one dbus object implementing the compatible
	// interface exists).
	_confCompatValues =
	util::SDBusPlus::getProperty<std::vector<std::string>>(
	util::SDBusPlus::getBus(), path, confCompatIntf,
	confCompatProp);
	}
	catch (const util::DBusError&)
	{
	// Compatible property unavailable on this dbus object
	// path's compatible interface, ignore
	}
	}
	try
	{
	_loadFunc();
	}
	catch (const NoConfigFound&)
	{
	// The Decorator.Compatible interface is not unique to one
	// single object on DBus so this should not be treated as a
	// failure, wait for interfacesAdded signal.
	}
	}
	else
	{
	// Check if required config(s) are found not needing the
	// compatible interface, otherwise this is intended to catch the
	// exception thrown by the getConfFile function when the
	// required config file was not found. This would then result in
	// waiting for the compatible interfacesAdded signal
	try
	{
	_loadFunc();
	}
	catch (const NoConfigFound&)
	{
	// Wait for compatible interfacesAdded signal
	}
	}
	}

	/**
	* @brief InterfacesAdded callback function for the compatible interface.
	*
	* @param[in] msg - The D-Bus message contents
	*
	* If the compatible interface is found, it uses the compatible property on
	* the interface to set the list of compatible values to be used when
	* attempting to get a configuration file. Once the list of compatible
	* values has been updated, it calls the load function.
	*/
	void compatIntfAdded(sdbusplus::message_t& msg)
	{
	if (!_compatibleName.empty())
	{
	// Do not process the interfaceAdded signal if one compatible name
	// has been successfully used to get config files
	return;
	}
	sdbusplus::message::object_path op;
	std::map<std::string,
	std::map<std::string, std::variant<std::vector<std::string>>>>
	intfProps;

	msg.read(op, intfProps);

	if (intfProps.find(confCompatIntf) == intfProps.end())
	{
	return;
	}

	const auto& props = intfProps.at(confCompatIntf);
	// Only one dbus object with the compatible interface is used at a time
	_confCompatValues =
	std::get<std::vector<std::string>>(props.at(confCompatProp));
	_loadFunc();
	}

	/**
	* Get the json configuration file. The first location found to contain
	* the json config file for the given fan application is used from the
	* following locations in order.
	* 1.) From the confOverridePath location
	* 2.) From the default confBasePath location
	* 3.) From config file found using an entry from a list obtained from an
	* interface's property as a relative path extension on the base path where:
	* interface = Interface set in confCompatIntf with the property
	* property = Property set in confCompatProp containing a list of
	* subdirectories in priority order to find a config
	*
	* @brief Get the configuration file to be used
	*
	* @param[in] appName - The phosphor-fan-presence application name
	* @param[in] fileName - Application's configuration file's name
	* @param[in] isOptional - Config file is optional, default to 'false'
	*
	* @return filesystem path
	* The filesystem path to the configuration file to use
	*/
	static const fs::path getConfFile(const std::string& appName,
	const std::string& fileName,
	bool isOptional = false)
	{
	// Check override location
	fs::path confFile = fs::path{confOverridePath} / appName / fileName;
	if (fs::exists(confFile))
	{
	return confFile;
	}

	// If the default file is there, use it
	confFile = fs::path{confBasePath} / appName / fileName;
	if (fs::exists(confFile))
	{
	return confFile;
	}

	// Look for a config file at each entry relative to the base
	// path and use the first one found
	auto it =
	std::find_if(_confCompatValues.begin(), _confCompatValues.end(),
	[&confFile, &appName, &fileName](const auto& value) {
	confFile = fs::path{confBasePath} / appName / value / fileName;
	_compatibleName = value;
	return fs::exists(confFile);
	});
	if (it == _confCompatValues.end())
	{
	confFile.clear();
	_compatibleName.clear();
	}

	if (confFile.empty() && !isOptional)
	{
	throw NoConfigFound(appName, fileName);
	}

	return confFile;
	}

	/**
	* @brief Load the JSON config file
	*
	* @param[in] confFile - File system path of the configuration file to load
	*
	* @return Parsed JSON object
	* The parsed JSON configuration file object
	*/
	static const json load(const fs::path& confFile)
	{
	std::ifstream file;
	json jsonConf;

	if (!confFile.empty() && fs::exists(confFile))
	{
	log<level::INFO>(
	std::format("Loading configuration from {}", confFile.string())
	.c_str());
	file.open(confFile);
	try
	{
	// Enable ignoring `//` or `/* */` comments
	jsonConf = json::parse(file, nullptr, true, true);
	}
	catch (const std::exception& e)
	{
	log<level::ERR>(
	std::format(
	"Failed to parse JSON config file: {}, error: {}",
	confFile.string(), e.what())
	.c_str());
	throw std::runtime_error(
	std::format(
	"Failed to parse JSON config file: {}, error: {}",
	confFile.string(), e.what())
	.c_str());
	}
	}
	else
	{
	log<level::ERR>(std::format("Unable to open JSON config file: {}",
	confFile.string())
	.c_str());
	throw std::runtime_error(
	std::format("Unable to open JSON config file: {}",
	confFile.string())
	.c_str());
	}

	return jsonConf;
	}

	/**
	* @brief Return the compatible values property
	*
	* @return const std::vector<std::string>& - The values
	*/
	static const std::vector<std::string>& getCompatValues()
	{
	return _confCompatValues;
	}

	private:
	/* Load function to call for a fan app to load its config file(s). */
	std::function<void()> _loadFunc;

	/**
	* @brief The interfacesAdded match that is used to wait
	* for the Inventory.Decorator.Compatible interface to show up.
	*/
	std::unique_ptr<sdbusplus::bus::match_t> _match;

	/**
	* @brief List of compatible values from the compatible interface
	*
	* Only supports a single instance of the compatible interface on a dbus
	* object. If more than one dbus object exists with the compatible
	* interface, the last one found will be the list of compatible values used.
	*/
	inline static std::vector<std::string> _confCompatValues;

	/**
	* @brief The compatible value that is currently used to load configuration
	*
	* The value extracted from the achieved property value list that is used
	* as a sub-folder to append to the configuration location and really
	* contains the configruation files
	*/

	inline static std::string _compatibleName;
	};

	} // namespace phosphor::fan